Agent and principal joint liability for GST applies when an agent supplies or receives goods on behalf of the principal. Liability to pay tax arises where an agent supplies or receives taxable goods on behalf of a principal: both the agent and the principal are jointly and severally liable for the tax payable on those supplies. The rule applies to agency transactions in which the agent effects the supply to third parties in the name of, or on behalf of, the principal; liability for the tax does not rest solely on the agent but attaches concurrently to the principal as well.